Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
  • D06N3/04—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds
  • D06N3/045—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds with polyolefin or polystyrene (co-)polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/02—Occupant safety arrangements or fittings, e.g. crash pads
  • B60R21/16—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L83/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon only; Compositions of derivatives of such polymers
  • C08L83/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D183/00—Coating compositions based on macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon, with or without sulfur, nitrogen, oxygen, or carbon only; Coating compositions based on derivatives of such polymers
  • C09D183/04—Polysiloxanes
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
  • D06N3/00—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof
  • D06N3/12—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins
  • D06N3/128—Artificial leather, oilcloth or other material obtained by covering fibrous webs with macromolecular material, e.g. resins, rubber or derivatives thereof with macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds, e.g. gelatine proteins with silicon polymers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
  • B60R21/00—Arrangements or fittings on vehicles for protecting or preventing injuries to occupants or pedestrians in case of accidents or other traffic risks
  • B60R21/02—Occupant safety arrangements or fittings, e.g. crash pads
  • B60R21/16—Inflatable occupant restraints or confinements designed to inflate upon impact or impending impact, e.g. air bags
  • B60R21/23—Inflatable members
  • B60R21/235—Inflatable members characterised by their material
  • B60R2021/23504—Inflatable members characterised by their material characterised by material
  • B60R2021/23509—Fabric
  • B60R2021/23514—Fabric coated fabric
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/04—Polysiloxanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G77/00—Macromolecular compounds obtained by reactions forming a linkage containing silicon with or without sulfur, nitrogen, oxygen or carbon in the main chain of the macromolecule
  • C08G77/70—Siloxanes defined by use of the MDTQ nomenclature
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/08—Copolymers of ethene
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1303—Paper containing [e.g., paperboard, cardboard, fiberboard, etc.]
  • Y10T428/1307—Bag or tubular film [e.g., pouch, flexible food casing, envelope, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/131—Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
  • Y10T428/1314—Contains fabric, fiber particle, or filament made of glass, ceramic, or sintered, fused, fired, or calcined metal oxide, or metal carbide or other inorganic compound [e.g., fiber glass, mineral fiber, sand, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/131—Glass, ceramic, or sintered, fused, fired, or calcined metal oxide or metal carbide containing [e.g., porcelain, brick, cement, etc.]
  • Y10T428/1317—Multilayer [continuous layer]
  • Y10T428/1321—Polymer or resin containing [i.e., natural or synthetic]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/13—Hollow or container type article [e.g., tube, vase, etc.]
  • Y10T428/1352—Polymer or resin containing [i.e., natural or synthetic]
  • Y10T428/1362—Textile, fabric, cloth, or pile containing [e.g., web, net, woven, knitted, mesh, nonwoven, matted, etc.]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
  • Y10T442/2041—Two or more non-extruded coatings or impregnations
  • Y10T442/2098—At least two coatings or impregnations of different chemical composition
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
  • Y10T442/2041—Two or more non-extruded coatings or impregnations
  • Y10T442/2098—At least two coatings or impregnations of different chemical composition
  • Y10T442/2107—At least one coating or impregnation contains particulate material
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T442/00—Fabric [woven, knitted, or nonwoven textile or cloth, etc.]
  • Y10T442/20—Coated or impregnated woven, knit, or nonwoven fabric which is not [a] associated with another preformed layer or fiber layer or, [b] with respect to woven and knit, characterized, respectively, by a particular or differential weave or knit, wherein the coating or impregnation is neither a foamed material nor a free metal or alloy layer
  • Y10T442/2139—Coating or impregnation specified as porous or permeable to a specific substance [e.g., water vapor, air, etc.]

Definitions

• This invention relates to a new adhesive coating composition, particularly for use on airbag fabrics, which is composed of a silicone polymer and an appreciable level of a copolymer of ethylene and a polar monomer.
• This coating provides excellent adhesive 0 properties to the coated fabric and provides a synergistic effect such that lower gas permeability upon inflation may be obtained with this coating than might be achieved with the silicone polymer alone. Additionally, such a coating allows maximization of the adhesion characteristics on one-piece woven airbag fabric such that blistering upon high-pressure inflation can be reduced, while retaining a high degree of inflation gas retention.
• Fabric 5 treated with this material in the manner described herein permits reduction in the cost of the coating itself (by reducing the use of expensive silicone polymers). Airbag fabrics and cushions, as well as methods of making and using such a novel airbag coating material are also encompassed within this invention.
• Airbags for motor vehicles are known and have been used for a substantial period of time. These devices are installed on the driver and passenger side of automobiles and, in the event of a collision, are rapidly inflated with gas, to act as a barrier between the driver or passenger and the steering wheel or dashboard of the automobile. 5' Coatings have been applied to fabrics, intended for use in automotive airbags, to resist s the unwanted permeation of air through the fabric and, to a lesser extent, to protect the fabric from detriment by the hot gases used to inflate the bags.
• Polychloroprene was the polymer of choice in the early development of this product, but the desire to decrease the folded size of the completed airbag, and the tendency of polychloroprene to degrade, with exposure to heat, 0 and release the components of hydrochloric acid (thereby potentially degrading the fabric component as well as releasing hazardous chemicals), has led to the almost universal acceptance of silicone (polydimethylsiloxane or similar materials) as a more suitable coating. In the quest for the most compact folded size possible, coating levels of polymer have dropped from around 2.5 ounces per square yard of fabric, to levels approaching 0.5 ounces per square yard (for driver's side and passenger airbags that do not generally require long- term gas retention).
• Driver side airbags are generally mounted within steering columns and exhibit relatively low air retention in order to act more as a cushion for the driver upon impact.
• Passenger-side airbags also comprise relatively high air permeability fabrics that permit release of gas either by percolation of the gas through the fabric or through vents integrated therein.
• Both of these types of airbags are designed to protect persons in sudden collisions and generally burst out of packing modules from either a steering column or dashboard.
• Side curtain airbags have been designed primarily to protect passengers during rollover crashes by retaining the inflation state for a long duration and generally unroll from packing containers stored within the roofline along the side windows of an automobile.
• Silicone polymers have excellent thermal properties but have relatively high permeability to gases, when compared to many other elastomers. This has not been a matter of concern in coatings used for driver side airbags, since the retention time requirements are very small, as noted above. The advent of side curtains, with higher air retention requirements is bringing to light the difficulties in achieving the desired retention properties at desired add-on levels.
• silicone polymers have, in the past, come at a price.
• the costs associated with such silicone compounds are generally quite high, particularly the costs required to provide sufficient coverage of target fabrics while best ensuring low permeability will continue as long as necessary.
• lower levels of other types of coatings thermoplastics and thermosets, such as polyurethanes, for example
• silicone coating materials are generally preferred over other polymer types due to their ability to withstand varied environmental and storage conditions over long duration.
• a one-piece Jacquard (for example) airbag cushion is more economical to produce due to the elimination of the need to first cut fabric portions from coated webs and subsequently sew them together.
• the distinct disadvantage of this system is that the target bag must be coated on the outside during production, (as opposed to a sewn bag in which the coated face is normally placed within the interior of the air bag). When the Jacquard woven bag is then deployed, inflation pressures may be transmitted through the fabric to the coating, applying a potentially delaminating force to that coating and creating a potential problem.
• the adhesion of the coating to the fabric is strong, then the diffusion forces are localized and, depending upon the strength of the coating film, may lead to a rupture of the film itself, whereupon the inflation gases can easily escape. If the airbag is intended as a side curtain, such inflation gas loss would severely reduce the effectiveness of the inflated airbag and jeopardize its ability to protect during a long duration rollover scenario. On the other hand, if the adhesion of the coating is less strong, then the diffusing force can be dissipated by localized delamination of the film without rupture thereof.
• inventive coating (which may be utilized on any fabric substrate) provides such an improvement.
• a coating is thus, broadly stated, comprised of a "two part" silicone polymer blended with a curing catalyst and a copolymer of ethylene and at least one type of polar monomer.
• such an inventive coating may be defined as a blend of a commercial two part silicone polymer with a copolymer of ethylene and a polar monomer, which, when present in an amount of at most 3 ounces per square yard over the entirety of a Jacquard woven one-piece side curtain airbag, provides sufficient low air permeability for said airbag that said airbag cushion exhibits a characteristic leak-down time after long-term storage (as discussed below, the time required for the internal pressure within said cushion to reduce from 20 psi to 10 psi) of at least 20 seconds (preferably, at least 25 seconds, more preferably at least 40 seconds, and most preferably, at least 55 seconds) of inflation.
• the inventive material is comprised of a silicone polymer, such as, without limitations, (e.g. a polyalkyl- or a polyphenylsiloxane), blended with a copolymer of ethylene and at least one polar monomer, such as, as non-limiting preferred substituents, methyl acrylate, vinyl acetate, and the like.
• a silicone polymer such as, without limitations, (e.g. a polyalkyl- or a polyphenylsiloxane)
• a copolymer of ethylene and at least one polar monomer such as, as non-limiting preferred substituents, methyl acrylate, vinyl acetate, and the like.
• the silicone polymer must be crosslinked, utilizing a catalyst.
• the catalyst may be any standard type, such as those based on platinum compounds, those based on peroxides (e.g. cumyl peroxide), materials, known in the trade as "condensation catalysts", and the like. Preferred for best results is the platinum-based catalyst.
• Such a cured silicone polymer (which still retains some catalyst material therein) is then blended with the ethylene/polar monomer copolymer constituent.
• Such a copolymer may be present in liquid form completely, or in any mix of solids and liquid; however, it is highly preferred that the copolymer first be, dissolved in an organic, highly volatile (low flash point) solvent (such as, without limitation, toluene, MEK, and the like, with toluene most preferred), to then leave a partially dissolved copolymer formulation for ease in handling and ease in incorporation with the silicone polymer.
• an organic, highly volatile (low flash point) solvent such as, without limitation, toluene, MEK, and the like, with toluene most preferred
• the level of solids of the ethylene/polar monomer copolymer is from 1-40%, more preferably from 10- 35%, and most preferably between about 15-25%.
• the volatile solvent can then be evaporated from the blend of silicone polymer and ethylene/polar monomer copolymer, and, upon subsequent exposure to sufficient heat, the entire formulation can then be cross-linked (cured) to form a uniform coating on a target airbag fabric or airbag cushion surface.
• the ethylene/polar monomer copolymer can be added in significant amounts to reduce the amount of silicone copolymer required to produce a successful airbag coating.
• the added ethylene/polar monomer component provides a level of low air permeability and adhesion that cannot be achieved by the cured silicone system alone. Such a system thus provides a very low permeability level when applied to airbag cushions and fabrics utilizing less silicone, thereby reducing the cost of the coating.
• ethylene-methyl acrylate copolymers such as NAMAC® 2036- 1, available from DuPont
• ethylene- vinyl acetate copolymers such as LENAMELT®
• the coating is produced by combining, in solution, 50-95 parts of a silicone polymer (preferably containing a platinum catalyst) and 5-50 parts of the ethylene/polar monomer copolymer.
• the silicone polymers for this inventive coating composition may be selected from any number of types of such polymers, including, without limitation, polyalkylsiloxanes, polyarylsiloxanes, copolymers of both, and the like, each including cross- linkable functionalities.
• the preferred polyalkylsiloxane is a polydimethylsiloxane and the preferred polyarylsiloxane is a polyphenylsiloxane, either of these materials may contain nondisclosed materials common to the compounding of commercial materials of this sort.
• the ethylene/polar monomer-containing copolymer may be a copolymer comprised of 60-85 weight percent ethylene and 15-40 weight percent methyl acrylate, preferably from 65-75 weight percent ethylene and 25-35 weight percent methyl acrylate, and most preferably a distribution of about 66-67 to about 33-34 of the two components. It may also be an ethylene containing copolymer comprised of 20-60 weight percent ethylene and 40-80 weight percent vinyl acetate, preferably from about 25-50 weight percent ethylene and from about 50-75 weight percent vinyl acetate, and most preferably about 40 and about 60 weight percent of these two components.
• the preferred curing agent is platinum catalyst, although other types, including inorganic types, such as palladium, etc., organic types, such as acyl peroxide, typically, but not limited to, benzoyl peroxide, may also be utilized for this purpose. Other well known curing agents may also used be used either supplemental to or as a substitute for the preferred platinum type.
• a solvent is preferably present to effectuate proper and thorough mixing of the components of the preferred coating composition, as well as the provision of a certain level of solids of the ethylene/polar monomer copolymer. More preferably such solvent is organic and volatile (i.e., evaporates easily at a relatively low temperature); most preferably such a solvent is toluene or similar type volatile liquid.
• the ethylene/polar copolymer compound is first dissolved in such a solvent to provide a relatively low solids level between about 1 to
• the copolymer is preferably added to the silicone polymer formulation in an amount of from about 10-35 parts of the total silicone copolymer present therein, more preferably from about 12-30 parts, and most preferably about 15-25 parts, depending on the copolymer chosen.
• the coating may also contain certain silane coupling agents to improve the adhesion of silicone containing coatings to fabrics (such as trimethoxysilanes, triethoxysilanes, mixtures thereof, and the like). Of particular interest are small amounts (e.g., from about 0.5-
• It may also contain pigments or colorants, (for identification or aesthetic reasons); inert ingredients (such as calcium carbonate or other materials classified as fillers), to reduce cost without also reducing the desired performance of the inventive coating as applied to the target fabric; flame retardants; and processing aids necessary to process the composition and make it suitable for use as an airbag coating.
• pigments or colorants for identification or aesthetic reasons
• inert ingredients such as calcium carbonate or other materials classified as fillers
• This inventive coating composition may be applied to any type of fabric substrate to provide effective low air permeability, as well as to alleviate seam tears and unraveling at cut edges.
• any type of fabric may be utilized in conjunction with the inventive coating, including those comprising natural fibers, such as cotton, ramie, abaca, wool and the like; synthetic fibers, such as polyester, polyamide, regenerated cellulose and the like; and inorganic fibers, such as glass, boron derivative fibers and the like.
• the target fabrics may be woven, knitted, non- woven and the like.
• the target fabric substrate comprises synthetic fibers, preferably, polyesters and polyamides and is preferably an airbag fabric.
• the airbag fabric is actually a Jacquard woven one-piece side curtain airbag cushion.
• the target airbag within this invention is a Jacquard woven cushion, formed from yarns comprising polyamide or polyester fibers.
• Such yarn preferably has a linear density of about 210 denier to about 630 denier.
• Such yarns are preferably formed from multiple filaments, wherein the filaments have linear densities of about 6 denier per filament or less and most preferably about 4 denier per filament or less.
• Such substrate fabrics are preferably woven using fluid jet weaving machines as disclosed in U.S. Patents 5,503,197 and 5,421,378 to Bower et al. (incorporated herein by reference). The fabric substrate with applied coating will hereinafter be referred to as an airbag base fabric.
• the formulation upon completion of compounding of the inventive coating, is preferably scrape coated across the airbag base fabric, the solvent (toluene, for example) is subsequently removed by evaporation by placing the treated airbag base fabric in an oven at 60-90°C, and the resultant coated airbag base fabric is then cured in an oven at 150-200°C to cross-link the remaining copolymer constituents and to ultimately form a thin coating.
• Scrape coating in this sense includes, and is not limited to, knife coating, in particular, knife over roll, knife over gap, knife over table, floating knife and knife over foam pad methods, to name a few method types. Since the coating composition exhibits excellent adhesive properties, generally only one coating pass is necessary to provide an effective, stable, low permeability coating on the target fabric surface.
• the final dry weight of the coating may vary with the intended use.
• the add-on maybe (preferentially) one ounce per square yard.
• the add-on would be 2 - 3 ounces per square yard, depending on the design of the bag.
• the resultant base fabric is also substantially impermeable to air, when measured according to ASTM Test D737, "Air Permeability of Textile Fabrics".
• the substrate fabric is preferably a woven nylon material. In the most preferred embodiment, such substrate fabric will be formed from fibers of nylon 6,6. It has been found that such polyamide materials exhibit particularly good adhesion when used in combination with the coating according to the present invention.
• characteristic leak-down time is intended to encompass the measurement of time required for the internal pressure of the target airbag cushion to decrease from an initial pressure of 20 psi to 10 psi. It is well known and well understood within the airbag art, particularly concerning side curtain (low permeability) airbag cushions, that retention of inflation gas for long periods of time is of utmost importance during a collision. Side curtain airbags are designed to inflate as quickly as driver- and passenger-side bags, but they must deflate very slowly to protect the occupants during roll over and side impact. Thus, it is imperative that the bag exhibits a very low leakage rate after the bag experiences peak pressure during the instantaneous, quick inflation. Hence, the coating on the bag must be strong enough to withstand the shock and stresses when the bag is inflated so quickly. Thus, a high characteristic leak-down time measurement is paramount in order to retain the maximum amount of beneficial cushioning gas within the inflated airbag.
• a target airbag cushion to retain such a high internal pressure for a minimum of 25 seconds, preferably 30 seconds, more preferably 45 seconds, and most preferably at least 55 seconds, is imperative to provide the maximum protection in the event of a rollover collision.
• Such a high leak-down time has heretofore been unavailable without utilizing very expensive high add-on levels of silicone coatings.
• the pressure of gas forced into the airbag after peak initial pressure is reached will not remain stable (it decreases during the subsequent introduction of inflation gas), and that the target airbag will inevitably permit escape of a certain amount of inflation gas during that time.
• the primary focus of such side curtain airbags is to remain inflated for as long as possible in order to provide sufficient cushioning protection to vehicle occupants during rollover accidents.
• the greater amount of gas retained the better cushioning effects are provided the passengers.
• the inventive airbag must retain at least half of its inflated gas volume 5 seconds subsequent to reaching peak initial pressure. Preferably, this time is 9 seconds, more preferably 15 seconds, and most preferably 20 seconds.
• the term, "after long-term storage” encompasses either the actual storage of an inventive airbag cushion within an inflator assembly (module) within an automobile, and/or in a storage facility awaiting installation.
• Such a measurement is generally accepted, and is well understood and appreciated by the ordinarily skilled artisan, to be made through comparable analysis after representative heat and humidity aging tests. These tests generally involve 107° C oven aging for 16 days, followed by 83° C and 95% relative humidity aging for 16 days and are universally accepted as proper estimations of the conditions of long-term storage for airbag cushions. Thus, this term encompasses such measurement tests.
• the inventive airbag fabrics must exhibit proper characteristic leak-down times after undergoing such rigorous pseudo-storage testing.
• NAMAC® 2036-1 copolymer from DuPont Polymers
• a coating composition was made in the manner of Example 1 in which the copolymer was NAMAC 2036-1 and the silicone polymer was RHODORSIL® LSR60HS (available from Rhodia) and diluted to form a resulting mixture of 50 percent solids.
• a coating composition was made in the manner of Example 1 in which the copolymer was NAMAC 2036-1 and the silicone polymer was 3730 Fabric Coating (available from Dow Corning) and diluted to form a resulting mixture of 50 percent solids (with toluene).
• Example 4 the copolymer was NAMAC 2036-1 and the silicone polymer was 3730 Fabric Coating (available from Dow Corning) and diluted to form a resulting mixture of 50 percent solids (with toluene).
• a coating composition was made in the manner of Example 1 in which the copolymer was NAMAC 2036-1 and the silicone polymer was Shin-Etsu Chemical Co., Ltd., X-34-1277
• a coating composition was made in the manner of Example 1 in which the copolymer was NAMAC 2036-1 and the silicone polymer was Shin-Etsu Chemical Co., Ltd., A2-37 A/B and diluted to form a resulting mixture of 50 percent solids (with toluene).
• a coating composition was made in the manner of Example 1 with the NAMAC 2036-1 replaced with LENAMELT® 500 (available from Bayer).
• These materials were then individually coated onto separate 420 denier, nylon 6,6 Jacquard woven one-piece airbag cushions of dimensions 800 x 250 mm, using a knife coater, dried for two minutes at 150°C, and cured for seven minutes at 170°C.
• the dry coating weight was 2 ounces per square yard.
• the characteristic leak-down time from an internal inflation pressure of 20 psi to 10 psi was then measured in accordance with the procedure delineated above. The measurements are tabulated below:

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• Organic Chemistry (AREA)
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• 2002
  • 2002-09-24 US US10/253,358 patent/US6846004B2/en not_active Expired - Fee Related
• 2003
  • 2003-08-06 EP EP03798686A patent/EP1549791A4/de not_active Withdrawn
  • 2003-08-06 JP JP2004539824A patent/JP2006500481A/ja active Pending
  • 2003-08-06 AU AU2003261407A patent/AU2003261407A1/en not_active Abandoned
  • 2003-08-06 KR KR1020057004991A patent/KR20050084824A/ko not_active Application Discontinuation
  • 2003-08-06 CA CA 2499178 patent/CA2499178A1/en not_active Abandoned
  • 2003-08-06 WO PCT/US2003/024614 patent/WO2004029344A2/en active Application Filing

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